ec 300 sub port

[lankydoug]

If the factory leaves .120" piston to head and .060" is enough to insure that there is no problems than what would you call giving up compression which = free torque/horsepower. If a guy buys a 300 it should run like a 300 not a 200. Blueprinting an engine will only gain the amount of power that was lost in production tolerances vs. putting clearances on the money. In this case I'm not sure if the reason is for the question as to why is the piston not clearing the port and are they all like that or if it's part of a search for missing power.

[widebear]

On my 03 mc250 I expermented wirh raising the cylinder to ensure the exhaust port being fully open at bdc and then cutting the squish to make up for the lost compression, it ran like a turd with a much, much narrower power band with way less torque. I finally removed one of the base gaskets to where the comp was 200 psi and it ran much better but more like a jap two stroke motocrosser than a enduro bike .On my next 250 ec I just went to the thinnest base gasket and left the head alone, the compression again 200 psi. The result being a sweet torquey, flexable woods engine that stokes everyone who rides it. Certainly not as much peak horsepower or overev as the mc but a totaly rideable and flexable power source that gives the orange and berg riders lots to worry about. who'd a thought.

[lankydoug]

Originally Posted by widebear

On my 03 mc250 I expermented wirh raising the cylinder to ensure the exhaust port being fully open at bdc and then cutting the squish to make up for the lost compression, it ran like a turd with a much narrower power band. I finally removed one of the base gaskets to where the comp was 200 psi and it ran much better.On my next 250 ec I just went to the thinnest base gasket and left the head alone, the compression again 200 psi. The result being a sweet torquey, flexable wood engine that stokes everyone who rides it, who'd a thought.

That makes sense to me since the critical part of the process is related to the upper edge of the port and the squish. When the piston is at the bottom it is no longer moving and the transfer port has already done it's job. Moving the upper edge changes timing and dynamic as well at static compression. If engines vary a lot from bike to bike it would back the reasoning to not copy your buddies jetting since his dynamic compression may not and probably doesn't duplicate yours.

[widebear]

{ quote If engines vary a lot from bike to bike it would back the reasoning to not copy your buddies jetting since his dynamic compression may not and probably doesn't duplicate yours.} unquote.



You make a very valid point there Lanky one. - The reason. which is why I have allways summarily dismissed the silver bullit jetting solutions being offered up by the bright and ambitious for mass consumption the lazy and inept.
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